Tuning Competing Electronic Phases in Monolayer VSe₂ via Interface Hybridization

Area of Science:

• Condensed Matter Physics
• Materials Science
• 2D Materials

Background:

• Two-dimensional transition metal dichalcogenides exhibit competing electronic phases crucial for understanding emergent ground states.
• Vanadium diselenide (VSe2) is a compelling material, with bulk hosting a charge density wave (CDW), while monolayers display distinct electronic behaviors.

Purpose of the Study:

• To identify and characterize distinct electronic regimes in mechanically exfoliated VSe2 flakes on Au(111) substrates.
• To elucidate the roles of interfacial hybridization, charge transfer, and strain as tuning parameters for electronic order in VSe2.

Main Methods:

• Mechanical exfoliation of VSe2 flakes onto Au(111) substrates.
• Investigation of electronic properties under varying substrate coupling, strain, and charge transfer conditions.

Main Results:

• Monolayers strongly hybridized with gold exhibit complete CDW suppression and moiré modulations.
• Bilayers maintain the bulk-like 4a × 4a CDW.
• Strained, decoupled monolayers in suspended regions stabilize a √3a × √7a CDW phase.

Conclusions:

• Interfacial hybridization, charge transfer, and strain are key parameters controlling electronic order in VSe2.
• Substrate interaction plays a reversible role in stabilizing different CDW phases in VSe2 monolayers.